<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script src="jquery-3.3.1.min.js"></script>
  </head>
  <body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <script>
      $("button").click(function () {
        $(this).css("background", "pink");
        $(this).siblings("button").css("background", "");
      });
    </script>
  </body>
</html>